This invention relates to devices for clearing blocked drains or conduits or the like. More particularly, this invention relates to a device which uses an aerosol propellant container for dispensing a desired amount of gas under pressure into a conduit through a nozzle to produce a clearing of the blockage.
The problem of clearing conduits, such as household drains, of blockages is a constantly reoccurring one. Many methods and devices have been used in the past for attempting to solve this problem. Chemical drain openers are well known in the art as is their principle of chemically attacking blockage material to effect its removal. However, some blockages are not susceptible of such chemical removal, at least not very easily. Furthermore, the chemical removal methods typically take a sufficient period of time to render them other than instantaneous.
Mechanical techniques for removing blockages are quite old. The common plumber's helper, which is basically a simple plunger, operates by creating a pressure buildup in the conduit to effectively remove the blockage from its point of lodgement. More recently, devices have been developed which use stored compressed gas for creating necessary pressure. An example of one such device is that of Caplan et al, U.S. Pat. No. 3,138,803. However, this patent device has a disadvantage in that the compressed gas cartridge found therein is only usable once. A similar device is that shown in Gasser, U.S. Pat. No. 2,939,154. As with the previous device, the cartridge must be replaced after each use. This is both inconvenient and costly.
With the advent of aerosol containers, the possibility of multiple gas discharges has become a reality. For example, Pittet, U.S. Pat. No. 3,823,427, utilizes an aerosol container having a conventional inverted vertical action aerosol valve of reciprocating type by which a liquified gas or propellant within the container may be selectively discharged. The selective discharge of the aerosol gas is accomplished by means of pressing a nozzle against the drain conduit opening, which compresses the helical biasing spring mounting the nozzle to the container. The nozzle, when so compressed, actuates a valve assembly comprising a conventional valve through a valve stem.
However, the force needed to move the nozzle against the biasing force of the spring is proportional to the distance traveled. In this manner, the device is rather stiff and difficult to operate. Further, the working distance traveled is rather large. Another disadvantage is the cost of manufacture and assembly of the spring, which is typically made of metal.